Revert "YARN-7180. Remove class ResourceType. Contributed by Sunil G."

This reverts commit 6bd81ab054da15ba65e81489e51c841e637c5e1c.

hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/resource/ResourceType.java

@@ -0,0 +1,28 @@
+/**
+* Licensed to the Apache Software Foundation (ASF) under one
+* or more contributor license agreements.  See the NOTICE file
+* distributed with this work for additional information
+* regarding copyright ownership.  The ASF licenses this file
+* to you under the Apache License, Version 2.0 (the
+* "License"); you may not use this file except in compliance
+* with the License.  You may obtain a copy of the License at
+*
+*     http://www.apache.org/licenses/LICENSE-2.0
+*
+* Unless required by applicable law or agreed to in writing, software
+* distributed under the License is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+* See the License for the specific language governing permissions and
+* limitations under the License.
+*/
+
+package org.apache.hadoop.yarn.server.resourcemanager.resource;
+
+import org.apache.hadoop.classification.InterfaceAudience.Private;
+import org.apache.hadoop.classification.InterfaceStability.Evolving;
+
+@Private
+@Evolving
+public enum ResourceType {
+  MEMORY, CPU
+}